Depth of consciousness monitor including oximeter

ABSTRACT

The present disclosure relates to a sensor for monitoring the depth of consciousness of a patient. The sensor includes a plurality of light sources, light detectors, and in some embodiments, electrodes. In an embodiment, the sensor includes reusable and disposable portions.

PRIORITY CLAIM

This application claims the benefit of priority under 35 U.S.C. §119(e)of the following U.S. Provisional Patent Application No. 61/387,457,titled “Depth of Consciousness Monitor Including Oximeter,” filed onSep. 28, 2010, and incorporates that application by reference herein inits entirety.

REFERENCE TO RELATED APPLICATIONS

This application is related to U.S. Provisional Patent Application No.61/387,426, titled “Magnetic Electrical Connector For Patient Monitors,”filed on Sep. 28, 2010, and incorporates that application by referenceherein in its entirety.

FIELD OF THE DISCLOSURE

The present disclosure relates to the field of oximetry. Morespecifically, the disclosure relates to oximetry technologies for depthof consciousness monitoring.

BACKGROUND OF THE DISCLOSURE

General anesthesia is often used to put patients to sleep and block painand memory during medical or diagnostic procedures. While extremelyuseful to caregivers, general anesthesia is not risk free, and thus,caregivers seek to maintain a depth of consciousness consistent with theneeds of a particular medical procedure. In short, there is a desire toavoid over and under dosing. However, as a patient's depth ofconsciousness may change from minute to minute, caregivers often employa host of monitoring technologies to attempt to periodically,sporadically, or continually ascertain the wellness and consciousness ofa patient. For example, caregivers may desire to monitor one or more ofa patient's temperature, electroencephalogram or EEG, brain oxygensaturation, stimulus response, electromyography or EMG, respiration,body oxygen saturation or other blood analytes, pulse, hydration, bloodpressure, perfusion, or other parameters or combinations of parameters.For many of the foregoing, monitoring technologies are individuallyreadily available and widely used, such as, for example, pulseoximeters, vital signs monitors, and the like.

In their depth of consciousness monitoring, caregivers may also userecording devices to acquire EEG signals. For example, caregivers placeelectrodes on the skin of the forehead to detect electrical activityproduced by the firing of neurons within the brain. From patterns in theelectrical activity, caregivers attempt to determine, among otherthings, the state of consciousness of the brain. Caregivers may also usecerebral oximeters to determine the percentage of oxygenation of thehemoglobin in the cerebral cavity inside the skull. Cerebral oximetry isdifferent from conventional pulse oximetry, which detects theoxygenation of blood in the body arteries. However, like pulse oximetry,caregivers place sensors on the body, in this case on the forehead, thatemit radiation and detect the radiation after attenuation by bodytissue. This attenuated signal includes information relating to theblood oxygenation of the brain. Directly measuring the blood oxygenationof the brain, or at least measuring physiological parameters indicativeof the blood oxygenation of the brain, provides information about thestate of brain function, such as, for example, brain oxygen consumption,not available by measurement parameters that determine only theoxygenation of the blood feeding the brain or by monitoring the brain'selectrical activity.

Today, there are several approaches to implementing a cerebral oximeter.One approach includes placing emitters on the forehead and spacingdetectors on the forehead at different distances from the emitters. Theemitters emit radiation at two or four different wavelengths and thedetectors output signals representing the detected attenuated radiation.An instrument compares a DC signal from the different detectors and usesthe difference as a basis for measurement. The underlying assumptionappears to be that the closer detector provides an indication of oxygensaturation of the tissue outside the cerebral cavity, while the furtherdetector provides an indication of the oxygen saturation of the tissueoutside and inside the cerebral cavity. Subtraction of the two is hopedto provide an indication of just cerebral oxygenation. In any event,caregivers use a rising or falling trend in this difference to makedeductions about the cerebral oxygen status in the patient. In somecases, instruments employing four wavelength systems also seek an outputvalue of oxygenation, as opposed to just a trend of the differencesignal. The foregoing approaches appear to be consistent withcommercially available instruments from Somanetics Corporation of Troy,Mich. and CAS Medical Systems, Inc. of Branford Conn. A significantdrawback to each of these approaches includes the cost of theinstrumentation and sensors is often prohibitively high.

Another approach to a cerebral oximeter includes deep tissue imaging.For example, this type of research exposes high frequency light to theforehead and attempts to measure time of arrival andscattering/absorption coefficients. While primarily still in a researchphase, it appears that the instrumentation could be less expensive thanthat disclosed above, perhaps even half the cost. However, even at thatsavings, this type of cerebral oximeter is still primarily in theresearch and development phase and still relatively costly. For example,the multiple optical benches provided in a single instrument generallyassociated with this type of design could cost more than three thousanddollars each.

Complicating the foregoing discussion is the realization that there islimited space on a patient's head for each of the different sensors.Particularly, where the forehead is the optimal measurement site inwhich to position EEG and brain oximetry sensors, drawbacks occur. Forexample, given the forehead's relatively small size, the foreheadprovides space for placement of a few sensors at the same time.

SUMMARY OF THE DISCLOSURE

Based on at least the foregoing, the present disclosure seeks toovercome some or all of the drawbacks discussed above and provideadditional advantages over any prior technologies. The presentdisclosure describes embodiments of noninvasive methods, devices, andsystems for monitoring depth of consciousness through brain electricalactivity and the oxygenation of the brain. Additional embodimentsinclude monitoring of heartbeat, arterial oxygenation, venousoxygenation, temperature, and other physiological patientcharacteristics. For example, the present disclosure includes acombination forehead sensor having EEG and brain oximetry components. Inan embodiment, the EEG components include electrical leads and the brainoximetry components include a plurality of light sources and detectors.Moreover, in an embodiment the forehead sensor includes a multisiteforehead sensor configured to be positioned above the eyebrows of apatient with connecting devices and cables traveling over the head andconveniently away from the body. Such positioning provides an ergonomicsensor along with increased safety from potential inadvertentinterference by the patient or caregiver.

In an embodiment, a light source system of the sensor includes low costoptical benches having self contained internal emission detectors, lightintegrators or prisms, mirrors and the like. For example, in anembodiment, a light source includes a cap configured to reflect lighttoward a splitting mirror focusing light to both an internal emissiondetector for evaluation of the intensity of the emitted light and anaperture for directing the light into the patient's tissue. The lightsource may also include opaque or other surfaces or walls configured toappropriately direct emitted light.

Further embodiments may transform a commercially available pulseoximeter into a brain oximetry unit. For example, a processing devicemay advantageously connect to a sensor or other data input connection ofa pulse oximeter to, for example, acquire power and open communicationbetween the devices. In an embodiment, the sensor would includecomponents for measuring the attenuation thereof. In an embodiment, thesensor would output a signal that represents the attenuated light. Thissignal would be similar to the output of a conventional pulse oximetersensor in that both attempt to be indicative of light attenuation.

The signal could then be transmitted to the pulse oximeter forprocessing, conditioning and displaying of the brain oxygenation on amonitor of the pulse oximeter. A conventional pulse oximeter would bereadily adaptable to process and display information from a brainoximeter sensor because the signals output by sensors of both devicesare similar in nature (as both are output from photodiode lightdetectors detecting light attenuated by tissue). Modifications to theoximeter may advantageously include the algorithms used to analyze thesignal from the sensors as cerebral oximeters may advantageously usedifferent wavelengths, frequencies, and different comparing and analysistechniques to determine oxygenation. However, one of ordinary skill willrecognize from the disclosure herein that algorithm changes often aremuch more straightforward and price competitive than significanthardware changes. This is especially the case when updating analready-installed base of monitors.

In another embodiment, a forehead sensor for monitoring the depth ofconsciousness of a patient is disclosed comprising a brain oxygenationsensor that includes at least one light source and two detectors, an eegsensor that includes electrical leads that make contact with the skin ofthe patient's forehead, a reusable portion that houses the light sourceand detectors of the brain oxygenation sensor and a disposable portionthat houses a plurality of EEG electrodes and is removably connectableto the reusable portion. The connector of the forehead sensor may alsoconnect to the disposable portion and the reusable portion and house themajority of the curicutiry and processing components for the EEG sensorand the brain oxygenation sensor. In embodiment, an interface betweenthe connector and the disposable portion may allow the disposableportion to be removably attached to the connector. The light source ordetector may also have a lip around their edge. In an embodiment, thereusable portion is directly connected to the disposable portion.

In an embodiment, a system for monitoring the depth of consciousness ofa patient is disclosed comprising a forehead sensor that includes abrain oxygenation sensor and a conventional pulse oximeter loaded withsoftware for displaying data related to the blood oxygenation level ofthe brain cavity data processed by the forehead sensor. In anembodiment, the conventional pulse oximeter may provide power to thesensor and be capable of communicating data with the sensor or providethe drive signal and process the signal from the detector of the brainoxygenation sensor. The forehead sensor may also contain all of thecomponents for processing the sign from detectors of the brainoxygenation sensor.

In another embodiment, a light source for a brain oxygenation sensor isdisclosed comprising a substrate, emitters attached to the substrate foremitting light with at least two different wavelengths, a detector fordetecting emitted light before it is attenuated by tissue, a capconnected to the substrate, and an aperture for the emitted light toexit the light source and enter the tissue site. The emitters may beLED's. In an embodiment a light diffusing material may be placed betweenthe emitters and tissue site to scatter light. The light diffusingmaterial may also be between the emitters and the detector and be madefrom a glass or epoxy that fills in around the emitters and detector. Inan embodiment, the cap may be reflective or non-reflective. In anotherembodiment, a splitting mirror may direct light either to the detectoror the aperture. In a further embodiment, a temperature sensor may beconnected to the substrate.

For purposes of summarizing the disclosure, certain aspects, advantagesand novel features of the disclosure have been described herein. Ofcourse, it is to be understood that not necessarily all such aspects,advantages or features will be embodied in any particular embodiment ofthe disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings and the associated descriptions are provided toillustrate embodiments of the present disclosure and do not limit thescope of the claims.

FIG. 1A illustrates an embodiment of a forehead sensor communicatingwith a brain oximetry unit, which in turn communicates with a pulseoximeter now configured to monitor a state of consciousness throughbrain oxygenation.

FIG. 1B illustrates an embodiment of the forehead sensor of FIG. 1Aincluding an ear pulse oximetry sensor.

FIG. 2A-2B illustrate block diagrams of embodiments of the brainoximetry unit of FIG. 1A.

FIGS. 3A-3O illustrate various embodiments of the forehead sensor ofFIG. 1A.

FIGS. 3A, 3N, and 3O illustrate embodiments of the forehead a sensorincluding reusable and disposable portions mated together.

FIGS. 3B-3C illustrate embodiments of the reusable portion includingvarious cerebral oximetry sensor components.

FIGS. 3D-3M illustrate embodiments of the disposable portion includingEEG, temperature and other parameter measuring components.

FIGS. 4A-4O illustrate various embodiments and views of light sources ofthe forehead sensor of FIG. 1A.

FIG. 4A-D illustrate perspective and side views of a light source of thecerebral oximeter according to embodiments of the present disclosure.

FIG. 4E illustrates a perspective view of the light source includinglight paths of a multi-faceted directing mirror according to anembodiment of the present disclosure.

FIG. 4F-G illustrate more perspective views of the light source.

FIG. 4H illustrates a further perspective view of the light sourcewithout a cap according to an embodiment of the present disclosure.

FIG. 4I illustrates a bottom view of the light source towards the topreflective covering according to an embodiment of the presentdisclosure.

FIG. 4J illustrates a perspective view of the light source with thereflective cover being composed of many portions according to anembodiment of the present disclosure.

FIGS. 4K-4M illustrate side views of the light source including asemi-reflectant mirror according to an embodiment of the presentdisclosure.

FIG. 4N illustrates a side view of the light source including a lightdiffusing material filling inside a cap according to an embodiment ofthe present disclosure.

FIG. 4O illustrates a side view of the light source with an angledsubstrate according to an embodiment of the present disclosure.

FIG. 4P illustrates a side view of the light source with a relativelyflat cap.

FIG. 5 illustrates an exemplary graph showing the calibratedrelationship of the emission detector output to the calibrated intensityof the emitter output according to an embodiment of the presentdisclosure.

FIG. 6 illustrates an embodiment of a forehead sensor communicating witha brain oximetry unit contained inside a connector, which in turncommunicates with a pulse oximeter configured to monitor and/or displaya state of consciousness through brain oxygenation.

FIGS. 7A-7E illustrate various embodiments and views of the foreheadsensor of FIG. 6.

FIG. 7A illustrates a perspective view of the sensor and connector withthe disposable portion of the forehead sensor detached from theconnector.

FIG. 7B illustrates a top view of the forehead sensor with thedisposable and reusable portion of the sensor connected.

FIG. 7C illustrates a side view of the forehead sensor with both thedisposable and reusable portion of the sensor connected.

FIG. 7D illustrates a front view of the forehead sensor with both thedisposable and reusable portion of the sensor connected.

FIG. 7E illustrates a bottom view of the forehead sensor with thedisposable and reusable portion connected.

FIGS. 8A-8D illustrate various embodiments and views of the foreheadsensor that include an EEG sensor.

FIG. 8A illustrates a perspective view of the sensor and connector withthe disposable portion of the forehead sensor detached from theconnector.

FIG. 8B illustrates a top view of the forehead sensor with thedisposable and reusable portion of the sensor connected.

FIG. 8C illustrates a side view of the forehead sensor with both thedisposable and reusable portion of the sensor connected.

FIG. 8D illustrates a bottom view of the forehead sensor with thedisposable and reusable portion connected.

FIGS. 9A-9E illustrate various embodiments and views of the reusableportion of the forehead sensor.

FIG. 9A illustrates a perspective view of the reusable portion andconnector of the forehead sensor with the reusable portion detached fromthe connector.

FIG. 9B illustrates a top view of the reusable portion of the foreheadsensor.

FIG. 9C illustrates a side view reusable portion of the forehead sensor.

FIG. 9D illustrates a front view of the reusable portion of the foreheadsensor.

FIG. 9E illustrates a bottom view of the reusable portion of theforehead sensor.

FIGS. 10A-10D illustrate various embodiments and views of the reusableportion of the forehead sensor.

FIG. 10A illustrates a top view of the reusable portion of the foreheadsensor.

FIG. 10B illustrates a side view reusable portion of the foreheadsensor.

FIG. 10C illustrates a bottom view of the reusable portion of theforehead sensor.

FIG. 10D illustrates an exploded perspective view showing an embodimentof the various layers of the reusable portion of the forehead sensor.

FIGS. 11A-11E illustrate various embodiments and views of the connectorof the forehead sensor.

FIG. 11A illustrates an exploded perspective view of the variouscomponents of the connector.

FIG. 11B illustrates a top view of the connector.

FIG. 11C illustrates a front view of the connector.

FIG. 11D illustrates a side view of the connector.

FIG. 11E illustrates a bottom view of the connector.

FIGS. 12A-12D illustrate various embodiments and views of the disposableportion of the forehead sensor.

FIG. 12A illustrates a perspective view of the disposable portion of theforehead sensor with a detached adhesive layer.

FIG. 12B illustrates a top view of the disposable portion of theforehead sensor.

FIG. 12C illustrates a side view of the disposable portion of theforehead sensor.

FIG. 12D illustrates a bottom view of the disposable portion of theforehead sensor that includes an attached adhesive layer.

FIGS. 13A-13D illustrate various embodiments and views of the disposableportion of the forehead sensor that include an EEG sensor.

FIG. 13A illustrates an exploded perspective view of the disposableportion of the forehead sensor with a detached adhesive layer.

FIG. 13B illustrates a top view of the disposable portion of theforehead sensor.

FIG. 13C illustrates a side view of the disposable portion of theforehead sensor.

FIG. 13D illustrates a bottom view of the disposable portion of theforehead sensor that includes an attached adhesive layer.

FIG. 14 illustrates an embodiment of an exemplary display showingpotential brain oximetry parameters that could be displayed in anembodiment of the brain oximetry sensor.

DETAILED DESCRIPTION

The present disclosure generally relates to patient monitoring devices.In order to provide a complete and accurate assessment of the state of apatient's various physiological systems, in an embodiment, a sensor mayadvantageously monitor one, multiple or combinations of EEG, cerebraloximetry, temperature, pulse oximetry, and other physiologicalparameters. In various embodiments, the sensor includes a disposableportion and reusable portion. For example, the disposable portion mayadvantageously include components near a measurement site surface (thepatient's skin), including, for example, an EEG, a temperature sensor,tape, adhesive elements, positioning elements, or the like. On the otherhand, the reusable portion may advantageously include more expensive orother components, circuitry or electronics, which, in some embodimentsinclude for example time-of-use restrictions for quality control or thelike. The reusable portion, can be used multiple times for a singlepatient, across different patients, or the like, often depending uponthe effectiveness of sterilization procedures. The reusable componentsmay include, for example, cerebral oximetry components, pulse oximetrycomponents and other components to measure other various parameters.

In an embodiment, the disposable portion of the sensor may include aninductance connection or other electrical connection to the reusableportion of the sensor, and the signal from both sensors could thereby betransmitted through a common cable to a brain oximetry unit. In anembodiment, the brain oximetry unit may include an analog to digitalconverter, various electrical filters, and a microcontroller forprocessing and controlling the various sensor components.

In an embodiment, a brain oximetery unit or additional signal processingunit could communicate with the forehead sensor disclosed herein and oneor more host display and patient monitoring stations. In an embodiment,the patient monitoring station may be a pulse oximeter. In anembodiment, the pulse oximeter may perform integrated display, datamonitoring and processing of patient parameters including a connectionfor power and data communication. In an embodiment, some or allcommunication may be through wired, wireless, or other electricalconnections. In an embodiment, the brain oximetry unit mayadvantageously be housed in a portable housing. In such embodiments, theunit may advantageously be physically associated with a monitoredpatient, such as, for example, attached in an arm band, a patient bedpouch, a hood or hat, a pocket of a shirt, gown, or other clothing, orthe like. In other embodiments, the unit may be entirely or partiallyhoused in a cable connector. In an embodiment, the signal processing andcondition unit could also monitor patient parameters through othersensors including, for example, ECG, Sp02 from the earlobe, finger,forehead or other locations, blood pressure, respiration throughacoustic or other monitoring technologies, or other clinically relevantphysiological parameters.

In an embodiment, the pulse oximeter communicates with a sensor, such asa forehead sensor including one or more light sources configured to emitlight at a patient's forehead. In an embodiment, the light source mayinclude one or more emitters or emitter systems, such emitters oremitter systems may be embedded into a substrate. In variousembodiments, the emitters could be either light emitting diodes(“LEDs”), lasers, superluminescent LEDs or some other light emittingcomponents. These components could be arranged in any pattern on thesubstrate and could be either a single light emitting source or severallight emitting sources. In an embodiment, the emitting components couldemit light that deflects off of reflective surfaces associated with acap of the substrate. The reflective cover could be any number of shapesor sizes and could be constructed to direct light to specific points ora point on the cap or substrate.

In an embodiment, a multi-faceted splitting mirror could reflect lightto an opening in the substrate that would allow the light to escape andbe emitted to an emission detector in an embodiment also housed in thelight source substrate. The emission detector may advantageously samplethe light providing feedback usable to create an optical bench or atleast optical bench properties of the light source, including, forexample, determinations of intensity, wavelength, or the like. In anembodiment, the light source may include a polarized filter foradjusting the emitter light, in some embodiments before exiting anopening in the emitter or being detected by the emission detector.

In an embodiment, a caregiver could analyze physiological informationcollected from the various sensors including a patient's temperature,EEG, brain oxygen saturation, stimulus response, electromyography orEMG, respiration monitor using acoustic sensor applied to the through,body oxygen saturation, glucose concentration, or other blood analytes,pulse, hydration, blood pressure, perfusion, or other parameters orcombinations of parameters to determine relevant information about thestate of a patient's well being. In another embodiment, a caregiver mayadvantageously analyze information collected from the various sensors tomore completely assess the overall depth of a patient's sedation andobtain an assessment superior to an assessment derived from monitoring asingle or a few of the parameters mentioned above.

Reference will now be made to the. Figures to discuss embodiments of thepresent disclosure.

FIG. 1A and 1B illustrate examples of a patient monitoring system 100.In certain embodiments, the patient monitoring system 100 measuresseveral physiological parameters including cerebral electrical activity,temperature, cerebral oxygenation, including venous and arterialoxygenation, arterial oxygenation at various other points on the body,various other blood analytes including total hemoglobin, glucose,lipids, stimulus response, electromyography or EMG, respiration, pulse,hydration, blood pressure, perfusion, or other parameters or combinationof other physiologically relevant patient characteristics. Theinformation from these physiological parameters can be evaluated usingtrend analysis, absolute and relative measures of certain parameters,combined or alone to evaluate the total wellness and current state of apatient at any point in time.

The patient monitoring system can include multiple or a single sensor120, a brain oximetry unit 140, and a pulse oximeter 150. The sensor 120can be any variety of shapes and sizes, and could be applied to avariety of measurement sites on a patient's skin including any locationon the forehead and temples or other location of the head. Also,electrodes designed to be placed at a measurement site covered with apatient's hair may advantageously be implemented in order to apply thesensor to any part of a patient's head that is covered with hair. Acaregiver or patient may fasten the sensor to the patient's head with avariety of mechanism including adhesive, straps, caps, combinations ofthe same, or other devices for fastening sensors to a patient's body orskin known in the art.

In an embodiment, the patient monitoring system 100 advantageouslyutilizes wireless communication to provide a portable unit toaccommodate an ambulatory patient, or other patient in transit. Forexample, in one embodiment, the brain oximetry unit 140 may be attachedto an arm band or included in an arm band or other device that iswearable by the patient, including in a cap, a hood, a sling or a pocketof a garment. In an embodiment, the sensor would communicate with thearm band brain oximetry unit 140 with a hard wired connection or awireless connection for convenience and flexibility of the patientobtained by eliminating excess wires.

In an embodiment, the portable brain oximetry unit 140, such as anarmband brain oximetry unit 140, could also communicate wirelessly withthe pulse oximeter 150. This would allow the brain oximetry unit 140 tobe transported between various caregiving facilities, each with theirown stationary pulse oximeters 150 without unhooking and reinsertinghardwired electrical connections. Instead, a brain oximetry unit 140could establish a wireless communication link with a stationary pulseoximeter 150 as the brain oximetry unit 140 is brought into proximity ofthe pulse oximeter 150. In an embodiment, the devices could establishthe connection automatically and patient data may be automatically sentfrom the brain oximetry unit 140 to the pulse oximeter 150 or theconnection may require input from a caregiver in the user interface ofeither of the devices. This will advantageously facilitate portabilityand seamless monitoring of a patient while being transported, forexample, from an ambulance to a hospital room or from room to room in ahospital.

In an embodiment, the pulse oximeter 150 may be a multi-parameterpatient monitoring station or other host device capable of monitoring awide variety of vital signs and blood constituents and other parametersor combinations of parameters such as those monitors commerciallyavailable from Masimo Corporation of Irvine, Calif., and disclosedherein with reference to U.S. Pat. Nos. 6,584,336, 6,661,161, 6,850,788,and 7,415,297, among others assigned to Masimo Corporation, and U.S.Patent Publication No. 2006/0211924, 2010/0030040, among others assignedto Masimo Corporation or Masimo Laboratories, Inc. of Irvine Calif.

FIG. 1B illustrates an embodiment of the patient monitoring system 100with a pulse oximeter 150 attached to a sensor 120 or through somephysical electrical conduction connection, wireless, or other suitableelectrical connection to the pulse oximeter 150. This willadvantageously provide additional information about the state of thearterial oxygenation of the blood being transported to the head. In anembodiment, the pulse oximeter 150 branches off the wiring from thesensor 120.

In an embodiment, a caregiver or the patient may attach the brainoximetry unit 140 directly to the patient's arm or other part orclothing of the patient through an armband with straps or some othermeans known in the art to connect a portable monitoring unit to apatient. In an embodiment, a brain oximetry unit 140 may be integratedinto a hat or other headgear wearable by the patient or some otherstructure near the patient. In an embodiment, brain oximetry unit 140can rest on a table or other surface near the patient.

In some embodiments, a brain oximetry unit 140 can be integrated withthe pulse oximeter 150. Alternatively, the brain oximetry unit 140 couldbe a module that is docked or somehow associated with a multi-parameterpatient monitoring station.

FIG. 2A and 2B show block diagrams of various embodiments of the brainoximetry unit 140, sensors 120, and pulse oximeter 150. In anembodiment, the brain oximetry unit 140 may utilize a processor 220which may be a micro-controller or other processor, which may control orcoordinate some or all of the functions of the various emitters 230 anddetectors 260 and other sensors 120 and in an embodiment, maycoordinate, process or condition, or manipulate the electronic data insome other manner, before communicating the data to the pulse oximeter150. Also, the processor 220 may receive instructions or data controlmessages from the pulse oximeter 150 to provide the appropriateconditioning and controlling of the various front end components of thevarious sensors 120 associated the pulse oximeter 150. In an embodiment,data transmitted between the brain oximetry unit 140, the pulse oximeter150, the sensors 120 and any other associated components of a patientmonitoring system 100 may be communicated by the devices usingelectrical wires, wireless communication, optical communication, RFID,LAN networks, or other electronic devices for communicating data knownin the art.

The brain oximetry unit 140 may also include various front endcomponents for the various sensors 120 that may be associated with thebrain oximetry unit 140. In an embodiment, front end components maytranslate and transmit instructions and control signals for driving thevarious sensors. In an embodiment, the front end components maytranslate, process, or transmit instructions and control signals to theemitting or light producing components of the sensor. The front endcomponents may also receive and transmit data acquired by the detectorsof the sensors to the microcontroller 220 or other processor 220.

These front end components could include front end components for avariety of sensors 120 including for sensors that detect bloodoxygenation, EEG, ECG, temperature, acoustic respiration monitoring(“ARM”) sensors, such as those available from Masimo Corporation ofIrvine, Calif., acoustic throat respiratory sensor, and brainoxygenation. In an embodiment, a caregiver could advantageously utilizea device with the ability to monitor the plurality of above mentionedparameters to more accurately determine a depth of a patient's sedation.In an embodiment, a front end component that would be associated with asensor 120 that detects brain oxygenation may have a sub componentdedicated to driving emitters 230 associated with a light source of thebrain oxygenation sensor and a sub-component associated with thedetector 230 or detectors 230 of the brain oxygenation sensor 300 forreceiving and transmitting the detected signals that pass throughvarious body tissues.

In an embodiment, one of the various sensors associated with the frontend components of the brain oximetry unit could be, for example, a bloodoxygenation sensor 310 which may be placed at various measurement siteson a patient's skin, including the earlobe, finger, forehead or otherplaces known in the art suitable for detecting blood oxygenation. Manysuitable pulse oximeter sensors 310 are known in the art such as thoseblood oxygenation sensors 310 commercially available from MasimoCorporation of Irvine, Calif., and disclosed herein with reference toU.S. Pat. Nos. 5,638,818, 6,285,896, 6,377,829, 6,580,086, 6,985,764,7,341,559, or others.

In an embodiment, another sensor 120 that may be associated with a frontend component of the brain oximetry unit 140 could be a temperaturesensor 320. The temperature sensor 320 could detect the temperature ofthe skin, the temperature inside the ear, the temperature under thetongue, or any other temperature measurement method known in the art. Inan embodiment, the temperature sensor 320 could be any suitablethermistor, or any other temperature sensor 320 known in the art capableof detecting a surface temperature of a patient's skin. Additionaltemperature sensor may advantageously provide feedback to the unit 140regarding the performance or temperature of one, combinations of, or allof the emitters 230.

An EEG sensor 330 may also be associated with the front end componentsof the cerebral oximeter 140. In an embodiment, the EEG sensor 330 maybe any of a variety of EEG sensors 330 known in the art. An EEG sensor330 could be applied to a patient at any of a multitude of locations andmeasurement sites on the skin of the head of a patient. In anembodiment, the EEG sensor 330 may include electrode leads that may beplaced on a measurement site in contact with the skin of the patient. Inan embodiment, the EEG 330 may monitor the electrical activity of apatient's brain through any number of electrodes, electrode leads, andchannels or other systems known in the art.

In an embodiment, the EEG sensor 330 may monitor and collect data from apatient's brain using 4 channels and 6 electrodes. In anotherembodiment, the EEG 330 may use 3 channels and 5 electrodes. In anotherembodiment, any variety or combination of sensors maybe be used that aresuitable for obtaining an EEG signal, for example, such a system isdisclosed in U.S. Pat. Nos. 6,016,4444, 6,654,626, 6,128,521, or thelike.

A brain oxygenation sensor 300 may also be associated with the front endcomponents of the brain oximetry unit 140. In an embodiment, the brainoxygenation sensor 300 includes a light source 230, and a detector 260.The light source 230 of the brain oxygenation sensor 300 includesemitter(s) that would emit light, sonic or other radiation into theforehead at one, two or other plurality of measurement sites located onthe skin of the patient at a plurality of predetermined wavelengths. Inan embodiment, the brain oxygenation sensor 300 would include a detector260 with photodiodes or other radiation detection devices to detect theradiation emitting from the patient at a one or two or a plurality ofmeasurement sites on the skin of the head of a patient. Many suitablebrain oxygenation sensors 300 and cerebral oximeters are known in theart including those disclosed in U.S. Pat. Nos. 7,072,701, 7,047,054, orsimilar sensors.

In an embodiment, the light source 230 of the brain oxygenation sensor300 may include an emission detector 260. In an embodiment, the emissiondetector 260 would detect the light emitted from the light source 230before passing through or contacting the measurement site of thepatient. In an embodiment, an output from the emission detector 230would be communicated to the micro-controller 220 in the brain oximetryunit 140, the processing unit in the cerebral oximeter 140 or, someother processing component associated with the patient monitoring system100 in order to calculate an approximate output intensity of the lightemitted by the emitter(s) 230. The micro-controller 220 or otherprocessor 220 could calculate the output intensity based on the outputof the emission detector 260 by comparing the data to calibration data.In an embodiment, the calibration data could include measurement ofintensity of light emitted from the emitter(s) 230 and correspondingmeasurements of output from the emission detector 260. This data couldthen be correlated to real time output from the emission detector 260while the oxygenation sensor 230 is in use to determine an actual orapproximate intensity of light or radiation being emitted by theemitter(s) 230 utilizing a calibration curve or other suitablecalculation or processing method. In an embodiment, the calibration datamay be stored in an EPROM or other memory module in the brain oximetryunit 140, the pulse oximeter 150, or other patient processing moduleassociated with the patient monitoring system 100.

In an embodiment, the detector 260 will detect light or other radiationemitted from the light source 230 after, in an embodiment, some of thelight has entered the measurement site on the patient and has beenattenuated by a patient's tissue. In an embodiment, the detector 260could be any number of detectors known in the art for detecting light orother radiation including photodiodes or other types of light orradiation detectors. In one embodiment, the detector 260 may convertdetected light or other radiation into a signal, for example, anelectrical output signal, which may represent the intensity or otherattributes of the radiation. In an embodiment, the signal from thedetector 260 may be sent to a brain oxygenation detector 260 front endlocated in the brain oximetry unit 140 for processing, conditioning ortransmitting to the pulse oximeter 150 or other patient monitoringprocessor. In one embodiment, the signal may be converted into a digitalformat by an analog to digital converted located in either the brainoximetry unit 140 or the pulse oximeter 150. In an embodiment, the datafrom the detector 260 of the brain oxygenation sensor 300 may beprocessed to determine the cerebral oxygenation of a patient's braintissue. In an embodiment, the processing of the data may includedetermining the changes of intensity between various wavelengths ofemitted and detected light of the cerebral oxygenation sensor 300.

In an embodiment, the cerebral oximeter 150 or multi-parameter patientmonitor acquires data from the brain oximetry unit 140 or sensor 120derived from physiologically relevant parameters. In an embodiment, thepulse oximeter 150 could give visual quantitative or qualitativeassessments of the patient's well being based on one or more of thevarious parameters or physiological attributes measured.

In an embodiment, a caregiver may utilize various physiologicalparameters to make a quantitative assessment of the patient's depth ofsedation as indicated by an index based on for example, a patient'stemperature, electroencephalogram or EEG, brain oxygen saturation,stimulus response, electromyography or EMG, respiration based onacoustic through sensors, body oxygen saturation or other bloodanalytes, pulse, hydration, blood pressure, perfusion, or otherparameters or combinations of parameters. In another embodiment, variousaspects of sedation could be assessed quantitatively or qualitativelybased on a visual representation of the patient's sedation in theaspects including hypnosis, responsiveness, muscle relaxation or otherclinically relevant facets of depth of anesthesia.

In an embodiment, the pulse oximeter 150 may supply power to brainoximetry unit 140 over a single line and data would be transferred backand forth between the brain oximetry unit 140 and pulse oximeter 150over a separate line or lines. In another embodiment, both power anddata could be transmitted over the same line or the same wire withmultiple lines in the wire. In another embodiment, data and power couldbe transmitted wirelessly or through an inductance connection betweenthe patient monitoring station and the signal processing unit or anyother suitable connections or transmission techniques known in the art.Induction or magnetic connections are also disclosed in U.S. patentapplication Ser. No. 13/246,768, titled “Magnetic Electrical Connectorfor Patient Monitors,” filed herewith on Sep. 27, 2011.

In an embodiment, the functionality of the brain oximetry unit 140 couldbe optionally controlled by the pulse oximeter 150. In an embodiment,the data and qualitative and quantitative assessments of a patient'swellness being could be displayed on either or both the brain oximetryunit 140 and pulse oximeter 150. Also, audible alarms and otherindicators could be displayed on either or both the brain oximetry unit140 and pulse oximeter 150 in response to various threshold breachesbased on the assessment of the patient's wellness determined from thevarious monitored parameters.

FIGS. 3A-3F illustrate several embodiments of the sensor 120. FIG. 3Ashows an embodiment of the sensor 120 wherein disposable 410 andreusable portions 420 of the sensor 120 are connected and overlayed ontop of one another. FIG. 3A shows six EEG electrodes 440 with tworeference electrodes and four active channel electrodes. FIG. 3A alsoshows the light source 230 and detector 260 components of the brainoxygenation sensor 300. Any number of suitable light sources 230 anddetectors 260 may be incorporated into the forehead sensor 120. All orsome of the above mentioned sensor components including the EEG leads440 and the brain oxygenation emitter 230 and detector 260 componentsmay be linked to a single chip for transmission of acquired signals anddrive signals or each component may be linked to its own individual chipthrough wires, or printed circuits, or other suitable electricalconnections.

In one embodiment, the light source 230 may include one or moreemitters. In one embodiment, the emitter could be a laser, or anysuitable apparatus for emitting near-infrared or other spectrum of lightincluding LEDS, super luminescent LEDs, or some other light emittingcomponents. In one embodiment, the light source 230 may be incorporatedwith the brain oximetry unit 140 and the light or other radiation couldbe emitted from the light source 230 onto a fiber optic cable whichwould transmit the light from the light source 230 to the measurementsite. In another embodiment, the emitter(s), including, for example, alaser or LED emitter(s), is embedded in the emitter 230 directly in theforehead sensor. Other fiber optics may be used after emission of thelight from the light source to equalize the intensity and distributionof the radiation over a cross sectional area of a beam of emitted lightafter it exits the emitter and before it enters the measurement site ofthe patient.

The detector 260 of the brain oxygenation sensor 300 may be any suitabledevice for detecting radiation including any combination of variousphotodiodes including InGas and Si photodiodes. In an embodiment, thedetector 260 is a photodiode connected directly to the forehead sensor120. In another embodiment, the forehead sensor 120 collects light thathas passed through patient tissue with a fiber optic cable or othersimilar apparatus that is positioned at an appropriate measurement site,for example on the patient's forehead. In an embodiment, the fiber opticcable could then transmit the collected light to the detector 260 of thebrain oxygenation sensor 300.

The EEG electrodes 440 may be any suitable electrodes for detecting theelectro-potentials on the surface of the skin of a patient's head. Inone embodiment, EEG electrodes 440 comprise a metal or other suitableconductor and utilize leads contacting the surface of the skin. Inanother embodiment, the electrodes 440 are gelled electrodes that makecontact through the skin via gel and have metal leads that come intocontact with the gel. In still yet another embodiment, the EEGelectrodes 440 may be glued to the forehead with any suitable patientdermal adhesive for connecting the EEG electrodes 440 and may haveelectrical conductivity. In an embodiment, potentials from the EEGelectrodes 440 are transmitted to the brain oximetry unit 140 forfurther conditioning, transmitting or processing.

FIGS. 3B and 3C show embodiments of a reusable portion 420 of the sensor120. In an embodiment, the reusable portion 420 includes the potentiallymore expensive components, including, for example, the sensor lightsource(s) 230 and detector(s) 260. The reusable portion 420 may alsoinclude the temperature sensor 320. The temperature sensor 320 may beany suitable sensor that can detect the temperature of the surface ofthe skin or other patient temperatures. In an embodiment, thetemperature sensor 320 may include a thermistor associated with thereusable portion 420 of the sensor 120.

In an embodiment, the reusable portion 420 includes an interface 510that couples the reusable portion 420 of the sensor to the brainoximetry unit 140. The interface 510 may be any suitable electrical ordata connection or communication port or device including, for example,a pin connector and receiver. Various other communication or electricalconnections known in the art may be utilized. In an embodiment, theinterface 510 is an inductance connection utilizing transformers tocouple a data and electrical connection across an insulator. In anotherembodiment, the interface 510 provides a data or electronic couplingbetween the reusable portion 420 and the disposable portion 410 of thesensor.

FIGS. 3D-3O illustrate various embodiments of a disposable portion 410of a forehead sensor 120 that, in an embodiment, attaches to ameasurement site of a patient's head and provides a base 520 to whichthe reusable portion 420 may be docked, mated or connected. FIGS. 3D-3Eillustrate an embodiment of a single chip disposable portion 410 of thesensor 120. The disposable portion 410 houses the components of thesensor 120 that may be less expensive than at least some of thecomponents contained in the reusable portion 420 of the sensor 120 andtherefore may be disposed after a single or multiple uses, either on thesame patient or different patients. The disposable portion 410 of thesensor 120 includes a tape substrate 530 that provides a base orsubstrate to which at least some of the components of the disposableportion 410 may adhere or be integrated. In an embodiment, the tape 530can be constructed from any suitable disposable material that willeffectively hold the components includes in the disposable portion 410to a patient's forehead or other measurement site. In an embodiment, thetape 530 includes a suitable dermal adhesive on a patient side of thedisposable portion 410 for temporary adhesion of the sensor 120 to apatient's skin.

In an embodiment, the disposable portion 410 of the sensor 120 mayincorporate various disposable components which may include, EEGelectrodes 440. In one embodiment, the EEG electrodes 440 may befastened to the tape 530 of the disposable portion 410. In anembodiment, the EEG electrodes 440 could be embedded in the tape 530 byany known adhesive in the sensor arts or any other suitable means forconnecting the EEG electrodes 440 that would allow the EEG electrode 440leads to be exposed on a patient side of tape 530 in an appropriateposition to come in close proximity to a measurement site of a patient'sskin. In an embodiment, EEG electrodes 440 may be gelled so that the gelcontacts the electrodes and a measurement site of a patient's skin toprovide an electrical path between the measurement site of the patient'sskin and the EEG electrodes 440. In an embodiment, the leads of the EEGelectrodes 440 are connected to a single chip by wires or other suitableelectrical connections, such a as a printed circuit.

FIGS. 3H, 3I, and 3M, illustrate a temperature sensor 320 associatedwith the tape of the disposable portion 410 of the sensor 120. In anembodiment, the temperature sensor 320 is a thermistor with thethermistor leads exposed on a patient contacting side of the tape 530,in order to facilitate the contacting of the leads of temperature sensor320 to a measurement site of a patient's skin. In an embodiment, thetemperature sensor 320 is connected to single chip through wires orother suitable electrical connections such as a flexible printedcircuit. In an embodiment, the temperature sensor 320 may be locatedanywhere on the tape 530, the disposable portion 410, or the reusableportion 420 of the sensor. In an embodiment, the leads for thetemperature sensor 320 may be near the center of tape 530 or anywhere onthe periphery of tape 530.

In an embodiment, the disposable portion 410 of sensor 120 may mate andconnect to or overlay the reusable portion 420 of the sensor 120. In anembodiment, the non-patient side of the tape 530 could mate or connectto the reusable portion 420 of the sensor 120 through some suitableadhesive on the tape 530 or some physical connection or mating means. Inan embodiment, the disposable portion 410 of the sensor 120 may alsocontain one or several sensory compartments 540. The sensorycompartments 540 may contain a transparent window or a space for thelight source 230 or the detectors 260 of the reusable portion 420 of thesensor 120 to emit and detect emitted light through the space ortransparent window.

In one embodiment, the light source(s) 230 and detector(s) 260 of thereusable portion 420 may align with the sensory compartments 540 whilethe reusable 420 and disposable 410 portions physically connect atplaces other than the sensory compartments 540 and light sources 230 anddetectors 260. In an embodiment, the light sources 230 and detectors 260of the reusable portion 420 of the sensor 120 may physically snap intoor somehow removably mate with the sensory compartments 540 of thedisposable portion 410 of the sensor 120. In one embodiment, the windowsof the sensory compartments 540 may contain certain filters to optimizethe wavelengths intensity, or other characteristics of the light thatpasses through the windows in the sensory compartments 540.

In still other embodiments, care may be taken to ensure sterilization ofthe reusable components is more straightforward, such as, for example,implementing matable electrical connections through magnetic, optical orother coupling mechanisms that can be mostly or entirely housed inseparate housings that are easily sterilized and mostly void of cavitiesor the like that can trap contamination.

FIGS. 3A, and 3N show an embodiment with the disposable portion 410 ofthe sensor electrically connected directly to the reusable portion 420of the sensor 120 through an interface 510. In an embodiment, theinterface 510 may be any suitable electrical connection such as a pinconnector, a snap in lead connector, an optical connection or aninductance connection.

FIGS. 3H and 3N show an embodiment of the sensor 120 with a pulseoximeter sensor 310 associated with the sensor 120. The pulse oximetersensor 310 shown in FIGS. 3H and 3N is an ear pulse oximeter sensor 310that emits and detects radiation to determine the oxygenation of theblood travelling through the arteries of the ear. Many suitable earpulse oximeter sensors 310 are known in the art such as those sensorscommercially available from Masimo Corporation and disclosed herein withreference to U.S. Pat. No. 7,341,599. In another embodiment, the pulseoximeter sensor 310 may be a forehead pulse oximeter sensor 310 or anyother suitable pulse oximeter known in the art or disclosed herein. Thepulse oximeter sensor 310 may be connected to the sensor throughelectrical wires, wirelessly or other suitable electrical or dataconnection. Data collected from the pulse oximeter sensor 310 may betransmitted to the brain oximetry unit 140 or pulse oximeter 150 or bothfor conditioning, or processing.

FIG. 3G illustrates a multi chip embodiment of the disposable portion410 of the sensor. In an embodiment, the various EEG electrodes 440 eachconnect to a separate chip that transmits the detected signal to theinterface 510. In an embodiment, the chip transmits the signal tovarious inductors integrated into interface 510 which transmit thesignal to inductors integrated into the reusable portion of theinterface 510.

FIGS. 3A, and 3N-3O show the reusable portion 420 of the sensor 120associated with or physically mated with the disposable portion 410 ofthe sensor 120. In an embodiment, the reusable 420 and disposableportions 410 of the sensor 120 physically mate at mating sections on thedisposable 410 and reusable 420 portions. In one embodiment, the matingsections are located near the light source 230 and detectors 260 on thereusable portion 420 and the sensory compartments 540 on the disposableportion 410. In an embodiment, the mating sections have rims 550 intowhich cerebral oximeter 300 emitters 230 and detectors 260 may beplaced, snapped into or mated. Rims 550 may be any suitable plastic orother flexible material, including metal that would allow the emitter230 and detector 260 to press or squeeze fit into place. This wouldallow the rims to physically hold the emitters 230 and detectors 260 inthe proper orientation.

FIGS. 4A-4O illustrate various embodiments of a light source 230 thatmay be utilized in a cerebral oximeter sensor 300. FIG. 4A shows anembodiment of the light source 230 which includes a substrate 610, guidewalls 620, a dividing wall(s) 630, a cap 640, reflective portions 650 onthe cap, a splitting mirror 660, and an aperture 670. In an embodiment,the light source 230 includes a substrate 610 to provide a base toassociate or attach the remaining components. In an embodiment, thelight source 230 includes at least one or a plurality of emitters 680,guide walls 620 attached to the substrate 610, and a dividing wall 630rising from the substrate 610.

FIG. 4B shows a perspective view of the light source 230 substrate 610without the cap 640 and one of the guide walls 620, a dividing wall 630,four emitters 680, an emission detector 260 and an aperture 670. In anembodiment, the dividing wall 630 prevents light emitted from theemitters 680 from directly contacting the emission detector 260 ordirectly exiting through the aperture 670. In an embodiment, theaperture 670 and emission detector 260 may be located anywhere on theside of the dividing wall 630 opposite the side associated with theemitters 680. In one embodiment, the detector 260 is close to thedividing wall 630 and the aperture 670 is spaced further from thedividing wall 630 than emission detector 260. The aperture 670 can beany suitable opening, slot, space, or gap in the substrate 610 of thelight source 230, in order to allow at least some of the light reflectedfrom the cap 640 or guide walls 620 to pass through the substrate 610and exit the light source 230. In an embodiment, the aperture 670 may bea transparent section filled with material that may have opticalproperties, including a filter or the like.

FIGS. 4C and 4E illustrate an embodiment of the light source 230 withthe substrate 610, emitters 680, cap 640, the splitting mirror 660, thedividing wall 630, the emission detector 260, the aperture 670 and thepolarizer 690 in light path of the light exiting aperture 670. FIGS. 4Cand 4E illustrate an example of one possible embodiment of the varietyof potential light paths taken by light emitted from the emitters 680.First, the light is emitted from the emitters 680 and subsequently maybe reflected or deflected by the cap 640 towards the splitting mirror660. Next, as the splitting mirror 660 includes many smaller reflectivecomponents that are angled in different directions, a light beam hittingthe splitting mirror 660, depending on its cross sectional area, maybroken into multiple beams. The reflective components will be angledeither to direct some of the light taking a certain path toward theemission detector 260 and some of the light taking a path leading to theaperture 670 and out of the light source 230. In an embodiment, thesesmaller reflective components of the splitting mirror 660 may berandomly spaced on the angled mirror to provide an even distribution orsampling of emitted light from the various emitters 680 to both theemission detector 260 and the aperture 670. The cap 640 may have areflective coating or be made of a reflective material in order toreflect light the emitters toward the splitting mirror 660.

In an embodiment, the cap 640 may have a curvature similar to thecurvature illustrated in FIGS. 4A, 4C, 4E-4G, and 4M and also a similarsubstrate 610, guide walls 620, splitting mirror 660, aperture 670, andemission detector 260 geometry to direct light emitted from the emitters680 to the emission detector 260 and the aperture 670. This isaccomplished by calculating the various angles and light paths of thecurvature of the cap, the various angles of the splitting mirror 660,and the reflective components and the various distances between thevarious components to maintain optimal light paths as described herein.

FIG. 4D shows an embodiment of the substrate 620 without the cap 640. Inan embodiment, the substrate 610 can be manufactured by etching outdepressions in a block of material to create the guide walls 620, thedividing wall 630, and the depressions for the emitter(s) 230, emissiondetector 260, and aperture 670. The substrate 610 may be made of anysuitable material. In one embodiment, the substrate 610 is made from amaterial that provides an even distribution of temperature such as aceramic material. FIG. 4F shows an outside view of the light source 230with dotted lines representing the splitting mirror 660 and the aperture670 associated with the substrate 610 of the light source 230. In anembodiment, the cap 640 includes back guide wall 625 attached to the cap640, the substrate 610, and the splitting mirror 660.

FIGS. 4G and 4H, and 4I show embodiments of the light source 230 fromdifferent perspectives. In an embodiment, the cap 640 is supported atleast in part by the guide walls 620 that extend down from the cap 640to the substrate 610. In an embodiment, the cap 640 is dome shaped. FIG.4I illustrates a light source 260 with eight emitters 680. Also shown isan embodiment of the splitting mirror 660 with several differentdirecting reflecting surfaces positioned in different orientations toangle the light rays either toward the aperture 670 or the emissiondetector 260. FIG. 4H shows the splitting mirror 660 as viewed frombelow the substrate 610. The dotted lines represent the outline of thecap 640, the aperture 670, and the emission detector 260.

FIGS. 4J and 4K illustrate an embodiment of the cap 640 that is dividedinto different sections, with each section tilted at a predeterminedangle to facilitate directing of the light paths from light emitted fromthe emitter(s) 680 to be directed toward the splitting mirror 660 whichwould then direct the light to the emission detector 260 or the aperture670. In an embodiment, the sections of the cap 640 may be arced to formthe guide walls 620. Also, the cap 640 may include straight segmentsthat are attached to the guide walls 620. In an embodiment, thesplitting mirror 660 may be formed in the cap 640, be the material ofthe cap 640, be fastened to the cap 640, partially to the cap 640, tothe guide walls 620 or to the substrate 610 or any combination thereof.

FIG. 4K illustrates the aperture 670 in the form of a semi-reflectantsplitting mirror 660 that allows some of the light to pass through themirror 660 and reflects the rest of the light to emission detector 260.In this embodiment, the aperture is behind the splitting mirror 660.

FIG. 4L illustrates an embodiment of the light source 230 with asplitting mirror 660 that includes both a semi-reflectant component anda completely or more strongly reflective component. In one embodiment,the splitting mirror 660 includes a first semi-reflectant mirrorpositioned at a first angle that reflects a portion of the emitted lightto the emission detector 260 or the aperture 670. The second reflectivesurface reflects the remaining light toward the aperture 670 or theemission detector 260, and in an embodiment, to the opposite of the twocomponents that the first reflective surface direct the light.

FIGS. 4K-4M also illustrate electrical connections 710 that power theemitters 680 and receive data from the emission detector 260 and areassociated with or printed on the side of the substrate 610 or othercomponents of the light source 260. These electrical connections 710 canbe any suitable electrical connection and may be printed on anycomponent of the light source 230 including the inside or outside of thecap 640.

FIG. 4M illustrates an embodiment with light source 230 that includes asemi-reflectant mirror 660 with the emission detector 260 located behindthe semi-reflectant mirror 660. In this embodiment, the emissiondetector 260 samples light that passes through the semi-reflectantmirror 660 and the aperture 670 emits light that is reflected from thesemi-reflectant mirror 660.

FIG. 4N illustrates an embodiment of the light source 230 where at leasta part of the space defined by the cap 640, the substrate 610 and theguide walls 620 are filled with light diffusing material 720. The lightdiffusing material 720 could be any suitable light diffusing material720 known in the art including an epoxy or other plastic material, fiberoptics, any epoxy mixed with beads or other materials. In an embodiment,the light diffusing material 720 may cause the light emitted from theemitters 680 to become increasingly evenly distributed in the domains ofat least range and intensity, as the path length of the light emittedfrom the emitter(s) 680 increases. In an embodiment, the light diffusingmaterial 720 will more evenly distribute the intensity and range of thelight that is incident on the emission detector 260 and the lightexiting the light source through the aperture 670.

FIG. 4O illustrates another embodiment of the light source 230 withemitters 680 on far sides of the substrate 610 and angled towards a semireflectant mirror 660 attached to the cap 640 or guide walls 620. Inthis embodiment, when the light is emitted onto the semi-reflectantmirror 660, some of the rays will pass directly through thesemi-reflectant mirror 660 and be detected by the emission detector 260.The other rays that do not pass directly through semi-reflectant mirror660 will be reflected. A portion of the reflected rays that have theappropriate incident angle on the semi-reflectant mirror 660 will exitthe light source 230 through the aperture 670 after reflecting off thesemi-reflectant mirror 660.

FIG. 4P illustrates another embodiment of the light source 230 that maynot require splitting mirror 660. In this embodiment, light rays areinstead directed to the detector 260 and the apertures 670 by thediffusion and scattering of the light through light diffusing material720. The light diffusing material 720 may be any suitable diffuser fordispersing light throughout the inside of the light source 230 includingglass, epoxy fill, glass beads, plastic, and any other diffuser,scatterer, mixer or combination known in the art. The light diffusingmaterial 720 may be filled in around emitters 680 or may be a componentin front of or around the emitters 680.

Additionally the cap 640 may reflect light diffused throughout thecavity back towards detector 260. The cap 640 may be reflective ornon-reflective. In an embodiment, the cap 640 absorbs light so that thedetector 260 senses light that has passed through the diffuser and hasnot reflected off the cap 260, so that it will be similar in quality,for example, intensity, to the light emitted through the apertures 670.The cap 640 may be made of a suitable metal including, for example,copper and/or gold. In an embodiment, the cap 640 is relatively straightand does not have a rounded profile in order to reduce the cost andcomplexity of manufacturing and reduce the bulkiness of the light source230. This is advantageous as a bulkier, larger sensor will add weightand make the sensor 120 more cumbersome on a patient's forehead.

In this embodiment, the apertures 670 may be directly above the emitters680 or to the left and right of the emitters 680 so that the emitterswill emit light directly outside the aperture 670 and most of the lightwill not have been reflected off of the cap 640 or other inside surfacesof the light source 230 before exiting the light source 230. This willprovide for simpler construction of the light source 230 and otheradvantages.

The emitters 680 in an embodiment, may be LEDs, or any other suitablelight emitting device known in the art. Also, in an embodiment, thetemperature sensor 320 will provide feedback for regulating theintensity of the emitters 680 in addition to the information obtainedfrom the detector 260 inside light source 230. The operator, therefore,will be able to maintain and determine an accurate intensity for theemitters 680, leading to more accurate results when processing thesignals detected by the detectors 260 of the brain oxygenation sensor300. In an embodiment, the embodiments disclosed with reference to FIG.4 comprise an optical bench whose manufacturing costs are significantlylower than those available to design manufacturers today. Diffusing,scattering, reflecting or mixing material, or combinations thereof, mayadvantageously be used to integrate emitted light, thereby providing anoptical bench from comparatively low cost manufacturing materials.

FIG. 5 illustrates an embodiment of the calibration curve 730 used todetermine the intensity of the light emitted from the light source 230though the aperture 670. In one embodiment, the intensity 740 of theemitted light is mapped with respect to the output 750 of the emissiondetector 260 of the light source 230. Measuring the output of emissiondetector 260 will allow the patient monitoring system 100 to calculate aclose approximation of the intensity 740 of light being simultaneouslyemitted from the light source 230 through the aperture 670.

FIG. 6 illustrates another embodiment of the patient monitoring systemthat incorporates that brain oximetry unit 140 into a connector 760 forthe sensor 120. This advantageously allows for a streamlined profile andreduced manufacturing costs of the brain oximetry unit 140 andassociated wires. In this embodiment, the circuitry for driving thefront end and controlling the drive signal of the brain oxygenationsensor 300 may be in the brain oximetry unit 140 which mayadvantageously be partially or entirely housed by the connector 760, ormay advantageously be partially or entirely housed by the pulse oximeter150 or other multi-parameter patient monitor. Additionally, thecircuitry for processing the signals detected by the detectors 260 ofbrain oxygenation sensor 300 may also be partially or entirely housed bythe connector 760.

In an embodiment, the connector 760 may also house various othercomponents that control and process the signals from various sensorsassociated with a patient monitoring system 100. For example, theconnector 760 may house the circuitry for a blood oxygenation sensor 310in, for example, an embodiment where the sensor 120 incorporates an earblood oxygenation sensor or other blood oxygenation sensor 310. Inanother embodiment, the circuitry for processing, detecting and/ordriving the signals for the temperature sensor 320, or EEG sensor 330may advantageously be incorporated into the sensor connector 760.

Also, the signal processing and conditioning circuitry processor for apatient sedation monitor capable of monitoring the EEG signals of apatient and providing feedback on the depth of sedation or awareness ofa patient undergoing anesthesia may be partially or entirelyincorporated into the connector. Sedation brain function monitors,including those similar to the SEDLine sedation monitor commerciallyavailable from Masimo Corporation of Irvine, Calif., and disclosedherein with reference to U.S. Pat. Nos. 6,128,521, 6,301,493, 6,317,627,6,430,437, among others assigned to Masimo Corporation. The connector760 may house the circuit board, with six channels for six detectors andthe SEDLine algorithm. In this embodiment, a conventional pulse oximetermay include upgraded programming to recognize the connection of a brainoximetry unit 140, whether separate or housed inside connector 760, andprovide communication and power to the unit 140. The unit 140 performsthe processing and other functionality for the sensor 120, includingstoring various algorithms for the associated sensors 120.

Integration of all or the majority of the associated circuitry andprocessing components of several different patient monitoring sensors120 in a single connector 760 advantageously provides a caregiver asimple device that can be attached to the patient's forehead or otherareas on the patient, to provide minimal discomfort to the patient andminimal amount of wires and connections to cause electrical interferencewith instruments in the hospital environment. Additionally, thecaregiver will need to spend less time hooking various sensors to apatient where each would otherwise require its own associated monitoringstation. Furthermore, this integration of sensor 120 processingcomponents allows some of the processing components to have sharedfunctionality and therefore saves considerably on manufacturing costs.For example, memory chips, processors, or other electrical componentsmay be shared by the various sensors in the connector 760.

FIGS. 7-13 illustrate various embodiments of the construction of thesensor 120. FIGS. 7A-7E illustrate an embodiment of the sensor withoutthe EEG sensor 330 incorporated and includes the disposable portion 410,reusable portion 420, interface 510, connector 760, sensor compartments540, light sources 230 and detectors 260. The part of the interface 510on the disposable portion 410 slides into the interface 510 on thereusable portion 420. The interface 510 on the reusable portion 420 maybe integrated into the connector 760 or may be separate and locatedelsewhere on the body of the sensor. In an embodiment, the interface 510on the disposable portion 410 may slide into the interface 510 on thereusable portion 420 and lock or be somehow be held into place until itneeds to be removed.

The interface 510 may include an EEPROM or other memory device from anauthorized manufacturer in order to provide quality control. Also, theinterface 510 may also include software programming or functionality fordetermining how many uses it has gone through, how many times it hasbeen used or applied to a patient, or the date of manufacture todetermine if it has expired. Also, the interface 510 may include anEEPROM for storing information unique to the electrodes that can be readby the patient monitoring system 100 or pulse oximeter 150. The pulseoximeter 150 or patient monitoring system 100 can then determine howmany electrodes are contained on the disposable portion 410, forexample, and other information.

FIG. 7E illustrates the placement of the light sources 230 and thedetectors 260 for the brain oxygenation sensor 300. The light source 230may be at the outer end of the sensor 120 and emits light into thecerebral cavity of a patient. The two detectors 260 closest to eachlight source 230 detect light emitted from the light source 230. Forexample, the right side light source 230 emits light into the head of apatient and some of the light is returned to the detector 260 closest tothe light source 230 and some returns to the detector that is just tothe right of the center of the sensor 120. The path that the lighttravels through the head of a patient to the closer detector generallydoes not enter the cerebral cavity and travels as deep as the skull. Thelight path taken by light detected by the further detector 260 generallyenters the cerebral cavity. In an embodiment, the signal from the firstdetector 260 can be subtracted from the second detector 260 in order toprovide the information necessary to calculate the cerebral oxygenationas disclosed herein.

FIGS. 8A-8D illustrate an embodiment of the sensor 120 with the EEGsensor 330 integrated into the sensor 120. In this embodiment, thedisposable portion includes the EEG electrodes 440, which areelectrically connected to the connector 760 through wires integratedinto the body of the disposable portion 410. In another embodiment, thedisposable portion 410 includes the EEG electrodes 440 for electricalcontact with a patient's skin. In this embodiment, the disposableportion may not include any wiring except for electrically connectingthe EEG electrodes 440 to the reusable portion 420.

FIGS. 9A-9E illustrate an embodiment of the reusable portion 420 thatallows the reusable portion to be disconnected from connector 760. Inother embodiments, the reusable portion 430 may be permanently connectedto the connector 760. In an embodiment, the reusable portion 420 may bemore difficult to disconnect from connector 760 than the disposableportion 410, and may require the operator to open or disassemble atleast a part of connector 760.

FIG. 9E illustrates an embodiment of the reusable portion 420 with lightsources 230 and detectors 260 some or all of which may take advantage ofseveral features to allow light piping. In an embodiment, the detectors260 and light sources 230 may have a raised lip 800 that contacts theskin to create a barrier that prevents light from escaping from thelight source 230 or detector 260 to the ambient. In an embodiment, theraised lip 800 may be black and absorbent, or reflective. The lightsources 230 and detectors 260 may also have a valley or depression onthe glass or other transparent or near transparent parts that increasesin depth towards the middle of the component. This valley or depressionwill also advantageously assist with light piping as greater and firmercontact will be made around the edge of the light source 230 or detector260 allowing less light to escape to the ambient from the light source230 or emanating from the skin to the detector 230.

FIGS. 10A-10D illustrate various embodiments of the reusable portion 420of the sensor 120. In an embodiment, the reusable portion 420 hasmultiple layers that are overlaid and connected together. In anembodiment, the layers include a top flexible sleeve 810, a flex circuitsupport 820, a flex circuit 830 and a bottom flexible sleeve 840. In anembodiment, the top and bottom flex circuit sleeves 810, 840, may bebonded together or connected together either at the edges or throughother means known in the art with the flex circuit support 820 and flexcircuit 830 inside and in-between. The top flexible sleeve 810 may bemade of silicone or another suitable material and may be white oranother color. The bottom flexible sleeve 840 may be made from siliconor other material and may be black. The flex circuit support 820 may bemade from cyrlex, polyester or another suitable material and providessupport for flex circuit 830. Flex circuit 830 may include EEPROM(s),the flexible circuit, the light sources 230 and detectors 260 for thebrain oxygenation sensor 300 and the interface 510. The bottom sleeveincludes recesses 850 for the light sources 230, detectors 260 andtemperature sensor 320.

FIGS. 11A-11E illustrate an embodiment of the connector 760. Theconnector 760, in this embodiment, includes a housing 860 that housesthe components of the connector 760, including for example, printedcircuit boards 870 for various functions, such as, for example, SEDLinemonitoring, brain oximetry, pulse oximetry, other blood parameter orphysiological parameter calculators, combinations of the same or thelike. The connector 760 also includes the interface 510 for thedisposable portion 410 and reusable portion 420. The interface 510 inthe connector 760 includes a slot 880 for interface 510 on thedisposable portion 410.

FIGS. 12A-12D illustrate an embodiment of the disposable portion 410that does not include the components for the EEG sensor 330 but includesthe components for the brain oxygenation sensor 300. In this embodiment,the sensor 120 includes the sensory compartments 540 and the interface510 which may include an EEPROM for security. In an embodiment, thedisposable portion 410 includes an adhesive layer 890 that includes alayer of adhesive and a base material to attach the adhesive layer tothe main body of the disposable portion 410. The adhesive layer 890includes the adhesive for attaching the sensor 120 to the patient'sskin. In an embodiment, where the disposable portion 410 does not havethe EEG sensor 330 components, the disposable portion 410 will notcontain any wires or any other electrical components allowing it to beinexpensively manufactured.

FIGS. 13A-13D illustrate an embodiment of the disposable portion 410that includes the EEG sensor 330 components. In this embodiment, thedisposable portion has the EEG electrodes 440 and wiring for the EEGelectrodes 440. The EEG electrodes 440 may include pads 900 for contactwith the patient's skin. The pads 900 fit into openings 910 in theadhesive layer 890 in order to make direct contact with the skin.

FIG. 14 illustrates an example of a display 920 that may be utilized forthe sensor 120. Shown is the brain oxygenation level (bO₂), the heartrate, blood oxygenation, and the sedation level from the SEDLine brainfunction monitor. As other sensors have been described or could beintegrated into the sensor 120 additional parameters may be shown on thedisplay 920.

Although the foregoing disclosure has been described in terms of certainpreferred embodiments, other embodiments will be apparent to those ofordinary skill in the art from the disclosure herein. Additionally,other combinations, omissions, substitutions and modifications will beapparent to the skilled artisan in view of the disclosure herein.Accordingly, the present disclosure is not intended to be limited by thereaction of the preferred embodiments, but is to be defined by referenceto the appended claims.

Additionally, all publications, patents, and patent applicationsmentioned in this specification are herein incorporated by reference tothe same extent as if each individual publication, patent, or patentapplication was specifically and individually indicated to beincorporated by reference.

What is claimed is:
 1. A forehead sensor for monitoring the depth ofconsciousness of a patient comprising: a first brain oxygenation sensorincluding: a first light source package configured to transmit opticalradiation towards a cerebral cavity of a patient, a first detectorlocated on the forehead sensor at a first distance from the first lightsource package, and a second detector located on the forehead sensor ata second distance from the first light source package, wherein the firstdistance is closer to the first light source package than the seconddistance; an EEG sensor including electrodes configured to detectelectrical signals proximate skin of the forehead of the patient; areusable portion configured to house the first brain oxygenation sensor;and a disposable portion configured to house the EEG sensor and isconfigured to be removably connectable to the reusable portion.
 2. Theforehead sensor of claim 1 comprising: circuitry and processingcomponents for the EEG sensor and the first brain oxygenation sensor;and a connector configured to connect the disposable portion and thereusable portion, the connector also configured to house a largerportion of the circuitry and processing components.
 3. The foreheadsensor of claim 2 comprising an interface between the connector and thedisposable portion, the interface configured to removably attach thedisposable portion to the connector.
 4. The forehead sensor of claim 1wherein the first light source package includes a barrier configured toretain light.
 5. The forehead sensor of claim 1 wherein at least one ofthe first detector or the second detector includes a barrier configuredto retain light.
 6. The forehead sensor of claim 1 wherein the reusableportion is directly connected to the disposable portion.
 7. The foreheadsensor of claim 1, comprising a second brain oxygenation sensorincluding: a second light source package configured to transmit opticalradiation towards the cerebral cavity of the patient; a third detectorlocated on the forehead sensor at a third distance from the second lightsource package; and a fourth detector located on forehead sensor at afourth distance from the second light source package, wherein the thirddistance is closer to the second light source package than the fourthdistance.
 8. The forehead sensor of claim 7, wherein the first brainoxygenation sensor is located at a first end of the forehead sensor andthe second brain oxygenation sensor is located at a second end of theforehead sensor.
 9. A light source for a brain oxygenation sensor, thebrain oxygenation sensor comprising: a substrate; a plurality ofemitters, attached to the substrate, configured to emit light with atleast two different wavelengths towards a tissue site of a patient; afirst detector configured to detect emitted light before it isattenuated by the tissue site of the patient to monitor the intensity ofthe emitted light; a cap configured to integrate the emitted lightwithin the light source; an aperture for at least some of the emittedlight to exit the light source towards the tissue site of the patient; asecond detector configured to detect light attenuated by the tissue siteof the patient; and a positioning element configured to position thelight source proximate to the tissue site of the patient.
 10. The lightsource of claim 9 wherein the emitters comprise LEDs.
 11. The lightsource of claim 9 wherein the emitters comprise incandescent lights. 12.The light source of claim 9 comprising a light diffusing materialpositioned within an optical path between the emitters and the tissuesite, the light diffusing material configured to scatters light.
 13. Thelight source of claim 12 wherein the light diffusing material comprisesa glass or an epoxy, said material positioned proximate the emitters andthe first detector.
 14. The light source of claim 9 comprising a lightdiffusing material positioned within an optical path between theemitters and the first detector, the light diffusing material configuredto scatter light.
 15. The light source of claim 9 wherein the capcomprises a reflective material.
 16. The light source of claim 9 whereinthe cap comprises a non-reflective material.
 17. The light source ofclaim 9 comprising a splitting mirror configured to directs light to thefirst detector and the aperture.
 18. The light source of claim 9comprising a temperature sensor operably connected to the substrate.